The fact that Facebook has collected a lot of information on its users should surprise no one. After all, many of use use the social network as a public journal of sorts, as well as a convenient, connected way to keep tabs on friends, loved ones and random acquaintances. It’s not a stretch to say that Facebook knows our whereabouts, our preferences, who are friends are and the major events lined up on our calendars.

But how well does Facebook really know us? Or, put another way, how much can we accurately deduce about our offline psychological profile from what we share on the social network? Is it possible to connect the data points to gain real insight into a person’s personality?

Yes, at least according to a recent study published in the scientific journal PNAS, which found that one small element of our Facebook activity – what we ‘like’ on the platform – can predict personality traits with a startling degree of accuracy, beating predictions from our work colleagues, our friends, our family and even, in certain cases, our spouses.

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This may feel unsettling, but it also reveals the future of personality-based recruitment, says Michal Kosinski, a computer science research associate at Stanford University and one of the study’s authors. Using a “laughable amount of the digital footprint,” i.e. people’s public Facebook likes (“we didn’t analyze web browsing or search queries…there’s nothing kinky, intimate or outrageous here,” he says) it’s possible to decipher an individual’s level of openness, conscientiousness, extraversion, agreeableness and neuroticism.

From an employer perspective, the findings point to a new method for assessing candidates’ personalities quickly, cheaply, efficiently and most importantly, accurately. “Now we know it’s better to look at your Facebook likes than to invite you in for a lengthy interview and ask you to fill out a questionnaire – a process that’s not just expensive, but very cheating prone,” Kosinski says.

The study’s researchers had more than 86,000 participants fill out a 100-item personality questionnaire, and then fed the results from 90 percent of the volunteers into a computer algorithm, along with their corresponding Facebook likes. The computer worked to draw links between openness, conscientiousness, extraversion, agreeableness, neuroticism and certain types of likes, and then used these connections to predict personality scores for the remaining 10 percent of the participants. With just 10 Facebook likes, it was able to generate a more accurate personality profile than a work colleague. With 65 likes it could beat a roommate or friend, 125 to best a family member and around 300 to do better than a husband or wife. (Keep in mind that the average Facebook user has 227 likes.)

These findings comes on the heels of another study carried out by Kosinski and his colleagues, which showed that a computer program, again exclusively using Facebook likes, could predict extremely personal (and statistically valid) information about a person – everything from his or her race, to IQ, to sexuality to drug use. As in this previous study, specific individual likes were highly correlated with certain traits. For example, “participants with high openness to experience tend to like Salvador Dalí, meditation, or TED talks,” the authors write, while “participants with high extraversion tend to like partying, Snooki (reality show star), or dancing.”

While the previous study “went wide” this one “focused on personality only,” explains Kosinski. “We dug really deep to optimize the model for that.” The same could be done for qualities such as IQ, political orientation or any of the other traits explored in previous study.

Possible applications

Dating, for one. The problem with online matchmaking is that people have a tendency to lie – about looks, age, occupation, but also about personality. “Using behavioral based assessments would improve the quality of the matches,” Kosinski says.

There’s an obvious potential for marketers, too. Personality affects what kinds of marketing we respond to, and companies (including Facebook) are already mining our in increasingly sophisticated ways. (Some universities, for example, are analyzing alumni’s social media activities in order to determine the best way to prompt individuals to donate.)

But the largest impact automated, accurate, and cheap personality assessment tools will have, Kosinski predicts, is on recruitment. Increasingly, personality is being trumpeted as “more important” than experience and harder skills, and corporations are experimenting with new, if relatively untested, ways to make hiring decisions based on the metric. (The Milwaukee Bucks recently hired a facial coding expert who claims he can decipher traits such as selfishness, resilience, and composure by studying the micro-expressions of potential players.)

Kosinski hopes that soon, companies will be able to evaluate candidates’ personality profiles compiled from their entire online behavior, encompassing everything from what they listen to on Spotify, to they search queries, to their purchasing habits. When you combine digital footprints from multiple sources – adding information about a person’s search history to what they’ve liked on Facebook – accuracy in predicting personality “will only go up,” he says. “It suggests that computers can not only beat us but they could probably beat us by large margins if we give them enough data.”

This is unsettling, especially when you consider that our online behavior can easily be parsed to decipher other personal details. “There is obviously a huge dimensional privacy worries – but I think to be honest, if we already know that we can predict accurately your sexual orientation and political and religious views, in a way who cares that we can also predict your personality profile,” Kosinski says. Instead, he believes individuals should push for greater transparency about their data so they can fully control who has access to it.

But he insists they will ultimately share it. Like other big data evangelists, Kosinski says the convenience of customization that comes with sharing data outweighs privacy concerns. “I’m willing to share [my digital footprint] with Facebook because in return, they offer me a very highly customized newsfeed, which I really enjoy,” he says. Similarly, he predicts job candidates will someday be willingly share their personality profiles with employers so that they can be matched with the appropriate position. “Like Netflix, except for job offerings,” he says.